Willis, 54, appeared in court Wednesday. He was arrested in March in South San Francisco after police stopped his car and said they found cocaine and drug paraphernalia. At the time, he faced a bench warrant for failing to appear at his October sentencing hearing in San Mateo County Superior Court on another drug charge.
A judge will decide Sept. 1 whether Willis should be sentenced to a residential drug treatment program or go to prison. He has been in custody since his arrest.
Defense lawyer Mark Geragos said Willis is serious about breaking the cycle of addiction.
"He's knocking on the door of double-digits for state prison," Geragos said outside court. "He's got to take it one step at a time ... get a handle on this."
Prosecutor Steve Wagstaffe said Willis needs to prove that he's committed to recovery.
"He's going to have to do some convincing," he said.
Willis, who co-wrote hits such as "Macho Man," "YMCA" and "In the Navy," left The Village People in 1980.